The present invention relates to tools for imparting force to mechanical elements located in confined spaces such as an automotive tool useful in the mounting and demounting of valve assemblies in internal combustion engines. Such valve assemblies are well known and are utilized in association with the intake and exhaust ports in the cylinder heads of such engines. Each assembly includes a valve and at least one compression spring encircling the stem thereof and positioned between the cylinder head and the spring retainer which also encircles the valve stem. The retainer is held in a position limiting the outward extension of the spring, as by means of a segmental tapered collet, wedgingly locked between the retainer and the valve stem by the spring action.
Until relatively recently, valve removal had been a difficult operation requiring the use of a specially designed C-clamp and involving a tedious, time consuming operation which resulted in substantial labor costs. Additionally, a plurality of different sizes of C-clamps were normally required to accommodate different valve assemblies due to substantial variations in compression spring size and other characteristics. In order to overcome the deficiencies inherent in the use of such apparatus, I invented a tool for mounting and demounting automotive valve assemblies which is described in my U.S. Pat. No. 3,315,339, issued Apr. 25, 1967. With such a tool, to demount a valve assembly, the tool is positioned endwise on the retainer and the mechanic simply delivers a sharp blow thereto with a rubber mallet or the butt of his hand, providing an impact sufficient to depress the spring, release and retain the collet segments and thereby permit separation of the valve assembly from the cylinder head. By employing a removable mounting element as a part of the tool disclosed in my aforementioned patent, a valve assembly can readily be mounted again in operative position by utilizing the impact of a sharp blow delivered to the tool with the valve assembly parts appropriately repositioned.
Although either of these operations can be performed in a very short amount of time, successful use of the tool requires adequate clearance proximate the end of the tool, when it is positioned over the valve assembly, with respect to surrounding components of the engine compartment, such as power steering units, brake cylinders, fender liners or similar components, to permit delivery of sudden and sufficient force to the tool. In the great majority of engine compartment arrangements, it is readily possible to substantially coaxially align the tool disclosed in my aforementioned patent with the valve stems and effect application of the requisite force for mounting or demounting of the valve assemblies. However, on some makes and models of vehicles, particularly with certain accessories installed, it is impossible to properly align the tool and/or there is insufficient clearance to strike the tool with either a mallet or the hand with sufficient impact to depress the spring. Cocking or angling the axis of my prior tool relative to the valve assembly to obtain adequate clearance to deliver an appropriate blow produces less satisfactory results than when the tool is properly aligned with the valve assembly since damage to the valve components may be effected, the collet segments may not be retained by the tool and can be lost in the engine compartment, or adequate spring compression may not be possible.